Bump rustfmt style_edition to 2024

The switch to edition 2024 Rust explicitly kept the rustfmt style at `2021`:
- https://github.com/bevyengine/bevy/issues/17960#issuecomment-2676153566

It would be nice to at some point bump this benefit from some of the ways formatting has gotten nicer.
Heres some of the ones i noticed testing this in bevy:
- long lines more readily broken onto the next line

- impl blocks with logs of generics and traits broken up more sensibly:

- long functions broken up more sensibly

- `tuple.0 .0` -> `tuple.0.0`

The primary issue why this was initially ignored still persists tho: The order of items in a single `use` changed to be alphabetical with uppercase first, which caused lots of changes over a large number of files. `git diff --stat` says `904 files changed, 3901 insertions(+), 3299 deletions(-)`

Start by locating the repository's rustfmt configuration and reviewing how Rust edition 2024 currently keeps rustfmt at style_edition 2021. Compare the formatting changes described in the issue, especially single-use ordering, and use the reported git diff --stat as a baseline. Done means the style edition is bumped and the resulting repository-wide changes are reviewed.

Written by the indexing model from the issue text.